(a) Field of the Invention
Exemplary embodiments of the invention relate to an oxide semiconductor, a thin film transistor including the oxide semiconductor, and a thin film transistor array panel including the thin film transistor.
(b) Description of the Related Art
Flat panel displays such as a liquid crystal display (“LCD”), an organic light emitting diode (“OLED”) display, an electrophoretic display, a plasma display, for example, typically include multiple pairs of electric field generating electrodes and an electro-optical active layer interposed between the pairs of electric field generating electrodes. The LCD includes a liquid crystal layer as the electro-optical active layer, and the OLED includes an organic light emitting layer as the electro-optical active layer. In flat panel displays, one of a pair of electric field generating electrodes may be connected to a switching element to receive an electric signal, and the electro-optical active layer converts the electric signal into an optical signal to display an image.
The flat panel display may include a display panel having a thin film transistor, e.g., a thin film transistor array panel. The thin film transistor array panel may be patterned with multiple electrodes and semiconductors, and masks may be used in the patterning process.
In the thin film transistor array panel, the semiconductor is an important factor in determining the characteristics of the thin film transistor therein. In the semiconductor including amorphous silicon, the charge mobility therein is low such that there is a limit in manufacturing a high performance thin film transistor. In the semiconductor including polysilicon, the charge mobility therein may be high such that the high performance thin film transistor may be effectively manufactured, while the manufacturing cost may be high and uniformity is low such that there is a limit in manufacturing a large-sized thin film transistor array panel.
Accordingly, a thin film transistor using an oxide semiconductor having high charge mobility and a high ON/OFF ratio of current compared with amorphous silicon and having a low cost and high uniformity compared with polysilicon has been researched.
Research on using zinc oxide (ZnO), tin oxide (SnO2) and zinc-tin oxide (ZnSnO) as the oxide semiconductor has progressed. Furthermore, research on adding a new material to an original material has progressed to improve the characteristics of the oxide semiconductor; however, a conventional method used to determine the added material, which is performed without a theoretical base in the periodic table, may be inefficient since a sample of the thin film transistor is manufactured, and the characteristics thereof are verified for the method.